.header{
  background-color: #91B4B3;
  .center{
    width: 1000px;
    height: 60px;
    margin: auto;
    position: relative;
    img{
      display: block;
      width: 140px;
      float: left;
      margin-top: 7px;
    }
    input{
      height: 35px;
      width: 250px;
      border: 0;
      float: left;
      position: absolute;
      top: 25%;
      left: 500px;
    }
    a {
      float: left;
      text-align: center;
      line-height: 60px;
      color: #FFF;
      text-decoration: none;
      font-size: 18px;
    }
    .login{
      float: right;
      margin-right: 100px;
    }
    .a1{margin-left: 50px;}
  }
}
.clearfix::after {
  content: "";
  display: block;
  clear: both;
}